ASTM E18-2003 标准硬度测试

Designation: E 18 – 03 Standard Test Methods for Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials1,2 This standard is issued under the fixed designation E 18; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. 1. Scope* 1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials, including test methods for the verification of machines for Rockwell hardness testing (Part B) and the calibration of standardized hardness test blocks (Part C). 1.2 Values stated in inch-pound units are to be regarded as the standard. SI units are provided for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. (See Note 6.) NOTE 1—The National Institute of Standards and Technology (NIST) maintains the national Rockwell hardness standards for the United States. In June 1998, NIST released new Rockwell C scale (HRC) test blocks as Standard Reference Materials (SRMs). The blocks were calibrated using NIST’s primary reference standardizing machine. The major benefit of the NIST standards is that their HRC levels are in line with the other industrialized countries around the world. The NIST HRC levels establish the hardness of materials slightly harder than the historical standards used in the United States for the past 75 years. The revision of E 18 requires that all performance verifications of Rockwell hardness indenters and hardness machines must be made using test blocks calibrated traceable to the Rockwell standards maintained by NIST. This can be accomplished through the use of commercial test blocks calibrated traceable to the NIST standards or by directly using the NIST SRMs. This requirement will apply only to the Rockwell scale(s) for which NIST supplies primary reference test blocks NOTE 2—In previous editions of this standard, ball indenters were required to be of hard steel. Beginning with this edition, tungsten-carbide balls are also allowed. This change is a first step in a planned future transition to eliminate steel balls and allow only the use of tungsten carbide balls. The elimination of steel ball indenters is scheduled to occur in about two years. The use of tungsten carbide balls will provide an improvement to the Rockwell hardness test because of the tendency of steel balls to flatten with use, which results in an erroneously elevated hardness value. In addition, NIST is planning to standardize the HRB scale using tungsten-carbide balls. As a result of this change, this edition also requires that when a ball indenter is used, the Rockwell hardness value must be reported with the scale designation followed by the letter “S” to indicate the use of a steel ball or the letter “W” to indicate the use of a tungsten carbide ball. The user is cautioned that Rockwell hardness tests comparing the use of steel and tungsten carbide balls have been shown to give different results. For example, depending on the material tested and its hardness level, Rockwell B scale tests using a tungsten carbide ball indenter have given results up to one Rockwell point lower than when a steel ball indenter is used. 2. Referenced Documents 2.1 ASTM Standards: A 370 Test Methods and Definitions for Mechanical Testing of Steel Products3 B 19 Specification for Cartridge Brass Sheet, Strip, Plate, Bar, and Disks (Blanks)4 B 36/B36 M Specification for Brass Plate, Sheet, Strip, and Rolled Bar4 B 96 Specification for Copper-Silicon Alloy Plate, Sheet, Strip, and Rolled Bar for General Purposes and Pressure Vessels4 B 97 Specification for Copper-Silicon Alloy Plate, Sheet, Strip, and Rolled Bar for General Purposes5 B 103/B 103 M Specification for Phosphor Bronze Plate, Sheet, Strip, and Rolled Bar4 B 121/B 121 M Specification for Leaded Brass Plate, Sheet, Strip, and Rolled Bar4 B 122/B 122 M Specification for Copper-Nickel-Tin Alloy, Copper-Nickel-Zinc Alloy (Nickel Silver), and Copper- Nickel Alloy Plate, Sheet, Strip, and Rolled Bar4 B 130 Specification for Commercial Bronze Strip for Bullet Jackets4 B 134 Specification for Brass Wire4 B 152 Specification for Copper Sheet, Strip, Plate, and Rolled Bar4 B 291 Specification for Copper-Zinc-Manganese Alloy 1 These test methods are under the jurisdiction of ASTM Committee E28 on Mechanical Testing and are the direct responsibility of Subcommittee E28.06 on Indentation Hardness Testing. Current edition approved June 10, 2003. Published August 2003. Originally approved in 1932. Last previous edition approved in 2002 as E 18 – 02. 2 In this test method, the term Rockwell refers to an internationally recognized type of indentation hardness test as defined in Section 3, and not to the hardness testing equipment of a particular manufacturer. 3 Annual Book of ASTM Standards, Vol 01.03. 4 Annual Book of ASTM Standards, Vol 02.01. 5 Discontinued, see 1981 Annual Book of ASTM Standards, Part 6. 1 *A Summary of Changes section appears at the end of this standard. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. Reproduced by IHS under license with ASTM Document provided by IHS for TRIODEM TECHNICAL SERVICES LTD, Order Number 01406785 on 2004/2/10 15:27:7 GMT. No reproduction or networking permitted. --`,`,`,```,```,`,,,,,`-`-`,,`,,`,`,,`--- (Manganese Brass) Sheet and Strip4 B 370 Specification for Copper Sheet and Strip for Building Construction4 E 4 Practices for Force Verification of Testing Machines6 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications7 E 140 Hardness Conversion Tables for Metals6 3. Terminology 3.1 Definitions: 3.1.1 calibration—determination of the values of the sig- nificant parameters by comparison with values indicated by a reference instrument or by a set of reference standards. 3.1.2 Rockwell hardness number, HR—a number derived from the net increase in the depth of indentation as the force on an indenter is increased from a specified preliminary test force to a specified total test force and then returned to the prelimi- nary test force. 3.1.2.1 Discussion—Indenters—Indenters for the Rockwell hardness test include a diamond spheroconical indenter and ball indenters (steel or tungsten carbide) of several specified diameters. 3.1.2.2 Discussion—Rockwell hardness numbers are al- ways quoted with a scale symbol representing the indenter and forces used. The hardness number is followed by the symbol HR and the scale designation. When a ball indenter is used, the scale designation is followed by the letter “S” to indicate the use of a steel ball or the letter “W” to indicate the use of a tungsten carbide ball. 3.1.2.3 Examples—64 HRC = Rockwell hardness number of 64 on Rockwell C scale. 81 HR30N = Rockwell superficial hardness number of 81 on Rockwell 30N scale. 72 HRBW = Rockwell hardness number of 72 on the Rockwell B scale measured using a tungsten carbide ball indenter. 3.1.3 Rockwell hardness test—an indentation hardness test using a verified machine to force a diamond spheroconical indenter (diamond indenter), or a ball indenter (steel or tungsten carbide) under specified conditions, into the surface of the material under test in two operations, and to measure the difference in depth of the indentation under the specified conditions of preliminary and total test forces (minor and major loads, respectively). 3.1.4 Rockwell superficial hardness test—same as the Rock- well hardness test except that smaller preliminary and total test forces are used. 3.1.5 verification—checking or testing to assure conform- ance with the specification. 4. Significance and Use 4.1 The Rockwell hardness test is an empirical indentation hardness test. Rockwell hardness tests provide useful informa- tion about metallic materials. This information may correlate to tensile strength, wear resistance, ductility, and other physical characteristics of metallic materials, and may be useful in quality control and selection of materials. 4.2 Rockwell hardness testing at a specific location on a part may not represent the physical characteristics of the whole part or end product. 4.3 Rockwell hardness tests are considered satisfactory for acceptance testing of commercial shipments, and have been used extensively in industry for this purpose. 4.4 Performance verifications of Rockwell hardness indent- ers and hardness machines shall be made using test blocks calibrated traceable to the Rockwell standards maintained by NIST when primary reference test blocks are available from NIST for the specific Rockwell scale. A. GENERAL DESCRIPTION AND TEST PROCEDURE FOR ROCKWELL HARDNESS AND ROCKWELL SUPERFICIAL HARDNESS TESTS 5. Principles of Test and Apparatus 5.1 General Principles—The general principles of the Rockwell hardness test are illustrated in Fig. 1 (diamond indenter) and Fig. 2 (ball indenters) and the accompanying Table 1 and Table 2. In the case of the Rockwell superficial test the general principles are illustrated in Fig. 3 (diamond indenter) and Fig. 4 (ball indenter) and the accompanying Table 3 and Table 4. 5.1.1 See Equipment Manufacturer’s Instruction Manual for a description of the machine’s characteristics, limitations, and respective operating procedures. Typical applications of the various hardness scales are shown in Tables 5 and 6. Rockwell hardness values are usually determined and reported in accordance with one of these standard scales. An indenter is forced into the surface of a test piece in two steps under specified conditions (see Section 7) and the difference in depth of indentation is measured as e. 5.1.2 The unit measurement for e is 0.002 mm and 0.001 mm for the Rockwell hardness test and Rockwell superficial 6 Annual Book of ASTM Standards, Vol 03.01. 7 Annual Book of ASTM Standards, Vol 14.02. FIG. 1 Rockwell Hardness Test with Diamond Indenter (Rockwell C Example) (Table 1) E 18 – 03 2Reproduced by IHS under license with ASTM Document provided by IHS for TRIODEM TECHNICAL SERVICES LTD, Order Number 01406785 on 2004/2/10 15:27:7 GMT. No reproduction or networking permitted. - - ` , ` , ` , ` ` ` , ` ` ` , ` , , , , , ` - ` - ` , , ` , , ` , ` , , ` - - - hardness test, respectively. From the value of e, a number known as the Rockwell hardness is derived. There is no Rockwell hardness value designated by a number alone be- cause it is necessary to indicate which indenter and force have been employed in making the test (see Table 5 and Table 6). 5.2 Description of Machine and Method of Test—The tester for making Rockwell hardness determinations is a machine that measures hardness by determining the difference in penetration depths of an indenter under two specified forces, called preliminary and total test forces. 5.2.1 There are two general classifications of the Rockwell test: the Rockwell hardness test and the Rockwell superficial hardness test. 5.2.2 In the Rockwell hardness test the preliminary test force is 10 kgf (98 N). Total test forces are 60 kgf (589 N), 100 kgf (981 N) and 150 kgf (1471 N). In the Rockwell superficial hardness test the preliminary test force is 3 kgf (29 N) and total test forces are 15 kgf (147 N), 30 kgf (294 N), and 45 kgf (441 N). The indenter for either test shall be of a spheroconical or spherical configuration. Scales vary by a combination of total test force and type of indenter. FIG. 2 Rockwell Hardness Test with Ball Indenter (Rockwell B Example) (Table 2) TABLE 1 Symbols and Designations Associated with Fig. 3 Number Symbol Designation 1 ... Angle at the top of the diamond indenter (120°) 2 ... Radius of curvature at the tip of the cone (0.200 mm) 3 P0 Preliminary Test Force = 10 kgf (98 N) 4 P1 Additional Force = 140 kgf (1373 N) 5 P Total Test Force = P0 + P1 = 10 + 140 = 150 kgf (1471 N) 6 ... Depth of penetration under preliminary test force before application of additional force 7 ... Increase in depth of penetration under additional force 8 e Permanent increase in depth of penetration under preliminary test force after removal of additional force, the increase being expressed in units of 0.002 mm 9 xx HRC Rockwell C hardness = 100 − e TABLE 2 Symbols and Designations Associated with Fig. 2 Number Symbol Designation 1 D Diameter of ball = 1⁄16 in. (1.588 mm) 3 P0 Preliminary Test Force = 10 kgf (98 N) 4 P1 Additional force = 90 kgf (883 N) 5 P Total Test Force = P0 + P1 = 10 + 90 = 100 kgf (981 N) 6 ... Depth of penetration under preliminary test force before application of additional force 7 ... Increase in depth of penetration under additional force 8 e Permanent increase in depth of penetration under preliminary test force after removal of the additional force, the increase being expressed in units of 0.002 mm 9 xx HRB Rockwell B hardness = 130 − e FIG. 3 Rockwell Superficial Hardness Test with Diamond Indenter (Rockwell 30N Example) (Table 3) FIG. 4 Rockwell Superficial Hardness Test with Ball Indenter (Rockwell 30T Example) (Table 4) TABLE 3 Symbols and Designations Associated with Fig. 3 Number Symbol Designation 1 ... Angle at the tip of the diamond indenter (120°) 2 ... Radius of curvature at the tip of the cone (0.200 mm) 3 P0 Preliminary Test Force = 3 kgf (29 N) 4 P1 Additional force = 27 kgf (265 N) 5 P Total Test Force = P0 + P1 = 3 + 27 = 30 kgf (294 N) 6 ... Depth of penetration under preliminary test force before application of additional force 7 ... Increase in depth of penetration under additional force 8 e Permanent increase in depth of penetration under preliminary test force after removal of additional force, the increase being expressed in units of 0.001 mm 9 xx HR30N Rockwell 30N hardness = 100 − e E 18 – 03 3Reproduced by IHS under license with ASTM Document provided by IHS for TRIODEM TECHNICAL SERVICES LTD, Order Number 01406785 on 2004/2/10 15:27:7 GMT. No reproduction or networking permitted. - - ` , ` , ` , ` ` ` , ` ` ` , ` , , , , , ` - ` - ` , , ` , , ` , ` , , ` - - - 5.2.3 The difference in depth is normally measured by an electronic device or by a dial indicator. The hardness value, as read from the instrument, is an arbitrary number which is related to the difference in the depths produced by the two forces; and since the scales are reversed, the higher the number the harder the material. 5.2.4 In accordance with the operating procedures recom- mended by the manufacturer of the hardness tester, the test is started by applying the preliminary test force causing an initial penetration of the specimen. Since measurement of the differ- ence in depth starts after the preliminary force has been applied, the dial gage pointer is set to zero if the instrument is a dial indicator model. On a digital readout instrument, the zero point is captured by the electronics automatically. The instru- ment shall be designed to eliminate the effect of impact in applying the preliminary test force. 5.2.5 The additional force is applied for the required dwell time and then removed. The return to the preliminary test force position holds the indenter at the point of deepest penetration yet allows elastic recovery to occur and the stretch of the frame to be factored out. The test result is displayed by the testing machine. 5.3 Indenters: 5.3.1 The standard indenters are the diamond spheroconical indenter and steel ball indenters having steel or tungsten carbide balls 1⁄16 , 1⁄8 , 1⁄4 , and 1⁄2 in. (1.588, 3.175, 6.350, and 12.70 mm) in diameter. 5.3.2 The diamond indenter shall conform to the require- ments prescribed in 13.1.2.1. 5.3.3 Indenter balls can be either tungsten carbide or hard- ened steel; however, tungsten carbide balls are recommended to reduce errors associated with the tendency of steel balls to flatten with use. Indenter balls shall conform to the require- ments prescribed in 13.1.2.2. 5.3.4 Dust, dirt, grease, and scale shall not be allowed to accumulate on the indenter as this will affect the test results. 5.4 Anvils—An anvil shall be used that is suitable for the specimen to be tested. The seating and supporting surfaces of all anvils shall be clean and smooth and shall be free from pits, deep scratches, and foreign material. If the provisions of 6.3 on thickness of the test piece are complied with, there will be no danger of indenting the anvil, but, if it is so thin that the impression shows through on the under side, the anvil may be damaged. Damage may also occur from accidental contacting of the anvil by the indenter. If the anvil is damaged from any cause, it shall be replaced. Anvils showing the least visible dent will give inaccurate results on thin material. 5.4.1 Cylindrical pieces shall be tested with a V-grooved anvil that will support the specimen with the axis of the V-groove directly under the indenter or on hard, parallel, twin cylinders properly positioned and clamped in their base. 5.4.2 Flat pieces shall be tested on a flat anvil that has a smooth, flat bearing surface whose plane is perpendicular to the axis of the indenter. 5.4.3 For thin materials or specimens that are not perfectly flat, an anvil having an elevated, flat spot about 1⁄4 in. (6 mm) in diameter shall be used. This spot shall be polished smooth and flat and shall have a Rockwell hardness of at least 60 HRC. Very soft material should not be tested on the spot anvil because the applied force may cause the penetration of the anvil into the under side of the specimen regardless of its thickness. 5.4.4 When testing thin sheet material with a ball indenter, it is recommended that a diamond spot anvil be used. NOTE 3—Caution: A diamond spot anvil should only be used with a superficial hardness tester and ball indenter. This recommendation should be followed, except when directed otherwise by material specification. 5.5 Test Blocks—Test blocks meeting the requirements of Part C shall be used to periodically verify the hardness tester. 6. Test Piece 6.1 The test shall be carried out on a smooth, even surface that is free from oxide scale, foreign matter, and, in particular, completely free from lubricants. An exception is made for reactive metals, such as titanium, that may adhere to the indenter. In such situations, a suitable lubricant such as kerosene may be used. The use of a lubricant shall be reported on the test report. 6.2 Preparation shall be carried out in such a way that any alteration of the surface hardness (for example, due to heat or cold-working) is minimized. 6.3 The thickness of the test piece or of the layer under test should be as dictated in Tables 7-9, and Table 10 and as presented graphically in Figs. 5 and 6. These tables were determined from studies on strips of carbon steel and give reliable results. For all other materials it is recommended that the thickness exceed 10 times the depth of indentation with a diamond indentor and 15 times the depth of indentation with a ball indentor. As a rule, no deformation should be visible on the back of the test piece after the test although not all such marking is indicative of a bad test. 6.4 For tests on convex cylindrical surfaces the corrections given in Tables 11-14 shall be applied. Corrections for tests on spherical and concave surfaces should be the subject of special agreement. When testing cylindrical specimens, the accuracy of the test will be seriousl